Friday, 31 January 2014

Sketchy Fact #26: Getting Biblical on the North American Plains

The largest gathering of animals ever observed was a swarm of Rocky Mountain Locusts that covered about 510,000 square km (197,000 square miles) of the American Plains in 1875. By contrast, Yellowstone National Park covers 8,983 square km (3,468 square miles). The locusts were extinct by 1902. No one particularly misses them.

Wednesday, 29 January 2014

Life in the Freezer: What’s the Deal with the Polar Vortex?

Special thanks to Emma in Kitchener, Ontario, Canada for suggesting this week's bone-chilling topic.

If you’ve spent much time east of the North American Rocky Mountains this winter you may have born witness to some freakishly cold weather. Cold snaps happen every now and then but what has been going on from the Canadian prairies all the way down to central Florida beginning in late December and peaking during the first few weeks of January has been pretty unprecedented. News outlets have taken to calling it “The Polar Vortex” because, quite frankly, that sounds awesome. But what has really been going on this winter?

Believe it or not (and I was incredulous to start) the Polar Vortex is not just a great buzz-term invented to sell newspapers. It is a real thing and most of the time it is a very good thing. Basically, as the Earth spins it causes wind to bend, blowing in a curve rather than a straight line. Meteorologists and fans of The Simpsons know this bending at the Coriolis Effect and it is at its most extreme at the North and South Poles. The bending is so extreme over the poles that the wind blows in a complete circle and creates what amounts to a massive hurricane. If you’ve ever seen footage of an arctic blizzard, you’ve seen the Vortex on home soil. The good news for people who live at more reasonable latitudes is that the  vortex traps freezing cold air at the top and bottom of the world

The problems that have arisen this winter have been the result of rapid warming over the Arctic Ocean. The phenomenon is called Sudden Stratospheric Warming (SSW) and we have known about it since the mid 1900’s. Essentially, when the polar stratospheric air rises in temperature by a few dozen degrees (K) over a period of about a week the usually stable Polar Vortex gets disrupted. It can no longer hold the coldest air on the planet in place and that air rushes south to the dismay of those guys who try to wear shorts all winter. The bone-chilling temperatures experienced across the continent haven’t just felt like arctic winds, they literally are arctic winds. The effect has been worsened by a slow jet stream failing to bring warm air from the south to combat the frigidity. To mix my movie references, it is a Perfect Storm straight out of The Day After Tomorrow.

So how bad has it been, really? Is this cold snap anything to write home about or are North Americans just getting a little wimpy? Well, if you were in Toronto or Chicago on January 7th (both hovering around -27 degrees C (-16 F)) you would have been better off at the South Pole (-21 C/-6 F). Interestingly, if you heard that Winnipeg, Manitoba was colder during the icy blast than the surface of Mars, you were both well-informed and grossly misled. It turns out equatorial Mars can reach temperatures of 27 C (81 F). Who knew?

Regardless of Martian weather, it has been impressively cold. New Year’s Eve in Winnipeg dipped down to -37.9 C (-36.2 F). Green Bay, Wisconsin set a record low on January 5th when it hit -28 C (-18 F).  And even the city of Saltillo in Mexico went subzero, recording a temperature of -6 C (21 F) on January 14.

Whenever something like this happens climate change skeptics are chomping at the bit to say something annoying like “So much for global warming!” When that happens to you, informed reader, feel free to share the fact that some researchers have suggested (even before the events of Dec-Jan 2013/14) that rising temperatures at the poles could disrupt the Polar Vortex and lead to extreme weather events (Weng, 2012). As anyone who has seen An Inconvenient Truth can tell you, temperature fluctuations are expected to be most severe around the Arctic and Antarctic.

So is this the new normal? Can people living on the leeward side of the Rockies start investing in dogsleds and parkas? It’s way too early to say, but probably not. Freaky weather happens from time to time, especially in the winter. The most we can do is keep an eye on things and adapt. If it turns out that we humans have accidentally flipped the freezer switch to high, we’re going to have to learn to live with it. At least we have Dennis Quaid to help with survival advice.

Full Journal Reference:

Weng, H. (2012). "Impacts of multi-scale solar activity on climate. Part I: Atmospheric circulation patterns and climate extremes". Advances in Atmospheric Sciences, 29 (4): 867–886. doi:10.1007/s00376-012-1238-1

Friday, 24 January 2014

Sketchy Fact #25: Eternal Jellyfish of the Spotless Mind

The jellyfish Turritopsis nutricula is biologically immortal. It can go back and forth from adult to infant whenever it wants and could live forever if there weren’t so many things in the ocean willing to kill it.

Wednesday, 22 January 2014

Deficient in Daylight: Why is Late January Such a Bummer?

If you’ve been feeling a little down this week odds are you are not alone. The third week of January and the third Monday of the year in particular is apparently the most depressing time of the year. “Blue Monday” as has come to be known was first publicized eight years ago by psychologist Cliff Arnall as part of a press release for a British travel agency. In spite of the obvious ulterior motives associated with the message and the medium, most of us would agree that the idea isn’t completely off base. 

The explanation offered by Arnall posited a number of culprits we could blame for the late January blues: feeling poor after Christmas, the fresh sting of failed New Year’s Resolutions, and decreased daylight hours just to name a few. Whether or not money and failure factor into it, there is certainly something to the idea that exposure to sunlight can impact our moods. A British survey reported that 79% of people feel that reduced daylight hours during the winter in temperate climates has a negative effect on their mental constitution.

Your body is not much more than a machine and your brain (as much as we like to put it on a pedestal) is just another piece of the puzzle. Just like with a car, the things our bodies are exposed to have a profound effect on the way that they function. Researchers at Johns Hopkins University have reported that altering the brain’s exposure to light throughout the day can increase levels of stress hormones in the body, impair sleep, and lead to a deficit in mental agility. 

Their study used mice and actually involved exposing them to light when their bodies were expecting darkness, but the results certainly highlight the vulnerability of the brain to changes in brightness. Their mice also quickly began to demonstrate behaviours associated with depression. Before you ask, a depressed mouse shows reduced movement and lack of interest in sugar and other pleasure seeking activities. While a depressed person might pursue sugar more actively than a happy one, the parallels are still striking. 

The reason for the changes brought on by light can be traced back to the body’s biological clock and the daily patterns of wakefulness and sleep that tend to correspond with light and darkness. These natural fluctuations are known as circadian rhythms and they have a profound impact on the behaviour of all living things. While we are probably most familiar with the daily rhythms of our own bodies, changes also occur on the scale of seasons and years. As we grow up, we are most active at different times of the day. A five year old might wake up at the crack of dawn to watch cartoons while his parents don’t rise until mid-morning and his teenaged sister doesn’t begin to stir until just before dinner. 

Likewise, seasonal changes impact the way we behave. Many animal species are thought to begin their annual migrations in response to changes in the length of the day and even the angle of the sun. Similarly, we humans are subject to the suns whims. Part of the explanation for why we don’t deal with the changes as well as butterflies, birds, and caribou could be that we evolved as an equatorial species and our internal clocks aren’t quite built for the huge swings in sunlight hours seen at more extreme latitudes. To put it on a more comprehensible time scale, a person from Hawaii might have a hard time dealing with 20+ hours of night in the extreme north if you suddenly dropped them in Iqaluit. 

There are a number of things we can do to combat the winter blues, however. Sitting near windows can help us make the most of the daylight available and exercising for a few minutes each day can help get mood enhancing chemicals flowing in your body and brain. For the exceptionally lazy, there are even special lights you can buy to help trick your body into thinking the sun is still up. However you cope, it helps to know that the sadness you feel isn’t actually related to the things going on in your life. Remember, we’re all in this together… except for the Hawaiians I guess.

Friday, 17 January 2014

Sketchy Fact #24: A Not Very Fun Game of Tag

Humans are the best endurance running animals on Earth. If you wanted to, you and a group of fit friends could chase a deer until it died of exhaustion.

Wednesday, 15 January 2014

Tough Toddlers: The Surprisingly Resilient Science of Children

We tend to regard babies as incredibly fragile versions of the real people they will eventually become. Each year parents spend billions of dollars padding the corners of their furniture and adding latches to cupboard doors that could thwart even the most devoted of safe-crackers. You can’t really blame them. It is part of human nature to protect our offspring. If humans didn’t have the instinctual urge to do everything in our power to protect kids, the species would be in real trouble. There is however a little talked about understanding in the scientific community that the very young are not as breakable as we sometimes think.

A quick survey of online news archives serves to highlight the exceptional durability of babies and toddlers. In September 2013 a 17 month old boy in Toronto, Canada survived a seven story fall from his family’s balcony. Only a month earlier, a one-year-old girl in Switzerland survived a fall from a cable car that killed both her parents. Then there is the story of Saskatchewan’s Karlee Kosolofski, who is in a league of her own.

On February 23, 1994 Karlee, then 2 years old, stumbled out of bed and wandered outside of her parents home in Rouleau, SK. It was approximately 3 AM and the temperature was -22 C (-7.6 F). Karlee was too small to reach the door handle that would allow her back in the house. Five hours later her mother found her virtually frozen solid. Attempts to revive her through CPR failed and she was rushed to the hospital, but her parents were sure it was too late. Karlee is now 19 years old and despite having had part of her left leg amputated due to extreme frostbite, she lives the life of a normal teenager. Doctors were able to thaw out her tissue and raise her body temperature from a world record low of 14.2 C (57.6 F) back up to a normal temperature of 37 C (98.6 F).

So what is going on here? How are these kids surviving such extreme physical events? The answer lies in the same force that produces the parental urge to protect them: evolution. Try as we might to keep kids out of harm’s way, they have a knack for finding it anyway. As a result, over millions of years, the bodies of children have developed certain defense mechanisms. Their bones are more flexible and greater in number, allowing them to absorb impact better. Relative to their size, they have great fat reserves giving them a bit of extra cushion and a build in source of emergency nourishment. Even a child’s mind is better equipped than most adults’ to cope with stressful situations.

In his book Deep Survival: Who Lives, Who Dies and Why, Laurence Gonzales describes a phenomenon in wilderness survival where children between the ages of 2 and 6 have one of the highest survival rates of any age group. This is because very young children don’t impose their expectations on the world. Instead they see situations for how they really are and accept them as fact. When they are tired, they sleep. When they are hungry, they eat. They don’t wander around to the point of exhaustion in search of the salvation that “must be around here someplace”.

So it appears that adults aren’t the only force looking out for kids, mother nature is also on their side. That is not to say that we don’t need car safety seats and childproof caps on medicine bottles. We grown ups have created a world that is full of more hazards than evolution can reasonably cope with. All I am saying is that parents shouldn’t feel like they are alone in the fight to keep their children safe. Of all the allies a person could have, biology is pretty good one.

*Disclaimer: Obviously, please do not try to subject children to this.

Friday, 10 January 2014

Sketchy Fact #23: Maybe the Biggest Sloth Won't Be Me After All

When the first people arrived in North America, the continent was home to a giant ground sloth that was 20 feet long and weighed about 2 tons. Thanks to DNA samples found in preserved hair, it has been suggested that one day scientists might be able to bring them back to life.

Wednesday, 8 January 2014

Bones, Boats, and Ice Sheets: Who were the first people in the Americas?

Ancient people can be hard to pin down. Archaeologists do about as much debating as they do digging, partly because no one wants to admit that the cool spearhead they found isn’t that important, and partly because the travel itineraries of prehistoric people can be incredibly hard to wrap you head around. 

Nowhere is this more true than in the Americas. Columbus was by no means the first European to arrive on the scene but he is generally credited as opening the can of worms that is the Archaeology of North and South America. When he made landfall in 1492 it rapidly became apparent that he hadn’t discovered anything new for humanity. People were everywhere. Millions of them. Ever since, scientists have been try to sort out where they came from. 

For most of the 20th century, the accepted wisdom was that the first people in the Americas were the Clovis people who left evidence in the form of stone tools around the New Mexico town of Clovis around 13,500 years ago. This all made good sense. Scientists had long known that around 14,000 years ago an ice-free corridor opened up in the previously impassible ice sheet that had been covering North America. The thing about ice sheets is that they take a lot of water to make and that water comes from the ocean. The upshot is that when the ice-free corridor opened up, sea levels were about 120 meters (400 feet) lower than today and Alaska was connected to Russia by what is known as the Berring Land Bridge. The Clovis people, is was said, cross the land bridge, threaded the needle of the ice-free corridor, and spawned all the first peoples of North and South America. Unfortunately, it appears that the story is too simple and comprehensible to be true. 

Doubts first began to surface in the 1970’s when two sites thousands of miles apart began to yield artifacts that were older than the Clovis culture. The first was in Pennsylvania at Meadowcroft rock shelter, where humans had apparently been making tools 2,000 years before the ice-free corridor opened up. The second site was in Chili and it revealed the remains of a tent structure dating to 14,800 years ago as well as a few tools. The problem with the Chilean site was that the tools looked nothing like those of the Clovis people. So either the Clovis people arrived sooner than we thought and abandoned their signature tools as soon as they hit South America, or there were people living in Chili while the Clovis people were still pondering the edge of an impassable Russian glacier.

Archaeologists responded to these findings in much the same way that all scientists initially respond to evidence that contradicts what they all believe. They either ignored it or made fun of it. It wasn’t until a team of respected archaeologists traveled to Chili in 1997 to validate the site that people began questioning the Clovis hypothesis

So if people didn’t walk to the Americas, how did they get here? Aside from the all-too-obvious explanation involving aliens, it would appear that they came by sea. Archaeologists have found evidence in sites dotting the Pacific coast that people were living in sea caves in Oregon and on islands off the coast of California at the same time, or slightly before Clovis people first arrived. This suggests that they used boats to travel along the coast all the way from Asia to North America. The idea isn’t as crazy as it seems, though. People made it to Australia (presumably by boat since Australia is an island) at least 45,000 years ago. Evidence suggests that the first North American could have followed a “kelp highway” along the southern edge of the glaciers and maintained much of the same diet for the entire trip. 

Still, more evidence has suggested that the same thing might have happened on the East coast of North America. There, researchers have found tools that look startlingly like those of the Solutrean culture of Western Europe. Tools dating to 22,760 years ago have been found with mastodon bones at sites in North Carolina. Even the people presenting this idea admit that the hard evidence does not yet exist to support it, but it’s worth keeping an eye on. 

The trouble with the coastal travel hypothesis is that most of the sites that would provide evidence in favour of it are now underwater. The upshot is that we are left scratching our heads. All we know for certain is that people have been in the Americas for a very long time and that the technology they used to get here is likely more advanced than we previously dared to think.

Friday, 3 January 2014

Sketchy Fact #22: Fishing Up The Past

The Coelacanth, a prehistoric fish was thought to be extinct until an African fisherman caught one in 1938. In 1997 a second species of Coelacanth was discovered off the coast of Indonesia.

Wednesday, 1 January 2014

Tracking Time: How Do Scientists Know How Old Stuff Is?

Happy New Year readers, and welcome to 2014! We hope you enjoyed your holidays! New years is an interesting concept. Obviously it makes sense to mark a starting and finishing point for each year if for no other reason than to keep things organized. You want to be able to look back at events in your life and say with certainty that they happened a given length of time ago, and years are a pretty handy tool for describing and keeping track of the passage of time.

Scientists also value the ability to talk about the past in terms of years, but for a long time they were unable to make the same confident conclusions that a person can make about their own life. When you are studying the length of time it took some species to evolve, or trying to decide if one dinosaur bone is older than another it can be a difficult task to know the very basics of what you are talking about.

People have spent a lot of mental energy developing ways to date things and over time we have pushed our view on the past further and further back, closer to the dawn of time. One of the oldest methods that people have used to talk about the age of things is a practice called dendochronology. Imagine you chop down a tree and want to know how old it is. Most people know that all you need to do to find out the answer is count the tree’s rings. One new ring is laid down each year, so it is easy to say that a tree you cut down today with 50 rings started growing in 1964. What most people would never think is that you can use the same strategy to talk about the age of old wooden furniture, buildings, and even the end of the last ice age.

It works by looking at trees with lifespans that overlap in time and comparing them to one another. The nice thing about tree rings is that they are not uniform in size. In wet years, when conditions are good, a tree might grow a lot and lay down a thick ring. In dry years, the rings tend to be narrower. By comparing the pattern of thick and thin rings on two trees that lived at the same time you can create a window further back into the past. If we found a tree with growth rings similar to the first ten from our 50-year-old tree on the outer edge of its trunk, we could say that the new tree died in 1964 and we could count its rings back to determine when it started growing. Scientists are shockingly good at this sort of thing and have dendochronological dates going back over 11,000 years.

But what do you do if the thing you are studying isn’t made of wood? We have all heard reports about a dinosaur bone being this many millions of years old, or a mammoth tusk being this many thousand, but how do scientists actually know how old that stuff is? It turns out the answer is atomic. 

As we learned in our discussion of radioactivity, some atoms have unstable isotope forms. What I didn’t tell you was that those unstable isotopes decay at predictable rates from one type of atom into another. For example, if you have a sample of carbon-14 (a carbon atom with 14 neutrons instead of the usual 12) you can be sure that half of that sample will decay every 5,700 years. This is called the half-life of the sample. The handy fact about carbon-14 is that it stops accumulating in an organisms body the moment it dies. By measuring the ratio of carbon-14 left in a sample of organic matter (hair, flesh, bone) compared to the stable non-decaying carbon-12, you can know the date of something up to 50,000 years old.

If you want to go even further back into the past you can do basically the same thing with different unstable elements found in rocks. Uranium-235 and Uranium-238 have half-lives of 704 million years and 4.5 billion years respectively, so they can tell you about the age of dinosaur fossils and of the Earth itself. If Uranium isn’t your thing, Thorum-232 has a half life of 14 billion years. And (for the scientist who likes to keep things just slightly ridiculous) Rubidium-87 has a half-life of 49 billion years, so you have plenty of choices.

It is nice to know that if we ever stop keeping track of New Years, we will have options for figuring out how old things are. A little dendochronology for things of the scale of human lives, some radio-carbon dating for items in human history, and uranium has us covered if things get really out of hand. It may seem complicated, but the ability to determine the age of things is one of the greatest achievements in all of science.